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Effects of electrophoretic deposition parameters on the photocatalytic activity of TiO2 films: Optimization by response surface methodology
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 452, Issue. 1 , 2014 , pp. 1-8 ; ISSN: 09277757 ; Vossoughi, M ; Feilizadeh, M ; Rashtchian, D ; Moradi, S ; Alemzadeh, I ; Sharif University of Technology
Abstract
In this work, the electrophoretic deposition method was utilized to immobilize TiO2 particles on stainless steel substrates. In addition, for the first time, statistics-based experimental design using response surface methodology was employed to investigate the effect of four key coating parameters (i.e. applied voltage, calcination temperature, photocatalyst weight percentage, and deposition time) on the photocatalytic degradation. Analysis of variance revealed that the proposed model was adequate. X-ray diffraction and scanning electron microscope were used to evaluate the effects of the parameters on degradation efficiency. The optimum applied voltage, calcination temperature, catalyst...
Comparison between Lagrangian and Eulerian approaches in predicting motion of micron-sized particles in laminar flows
, Article Atmospheric Environment ; Vol. 89, issue , 2014 , Pages 199-206 ; ISSN: 13522310 ; Rismanian, M ; Monjezi, M ; Zendehbad, M ; Fatehiboroujeni, S ; Sharif University of Technology
Abstract
Modeling the behavior of suspended particles in gaseous phase is important for diverse reasons; e.g. aerosol is usually the main subject of CFD simulations in clean rooms. Additionally, to determine the rate and sites of deposition of particles suspended in inhaled air, the motion of the particles should be predicted in lung airways. Meanwhile there are two basically different approaches to simulate the behavior of particles suspension, Lagrangian and Eulerian approaches. This study compares the results of these two approaches on simulating the same problem. An in-house particle tracking code was developed to simulate the motion of particles with Lagrangian approach. In order to simulate the...
Probable thermal effects of plasma impulse action on reservoirs
, Article Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources, 2 April 2012 through 5 April 2012 ; April , 2012 ; Amani, S ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2012
Abstract
Plasma impulse technology (PIT) is one of the most innovative methods among the oil recovery enhancement (EOR) jobs. Although the low cost and persistent effects of this method has attracted researchers attentions to its self, the governing mechanisms of reservoir remediation in this method are still shrouded in mystery. This study presents a brief discussion on probable thermal mechanisms which govern the interaction between reservoir formation and plasma impulse jet. Minerals dissociation, opening the fused pathway and organic deposits melting seem to be of the most important thermal effects
Fabrication of aluminum nitride coatings by electrophoretic deposition: Effect of particle size on deposition and drying behavior
, Article Ceramics International ; Volume 37, Issue 1 , 2011 , Pages 313-319 ; 02728842 (ISSN) ; Zarabian, M ; Alizadeh, P ; Sadrnezhaad, S. K ; Sharif University of Technology
Abstract
Electrophoretic technique was used to deposit micro- and nano-sized aluminum nitride coatings on stainless steel surfaces by using a well-dispersed stable suspension produced by addition of AlN powder plus a small amount of iodine to ethanol. Parabolic regime governed the deposition. Electrophoretic deposition for 240 s at 100 V resulted in formation of a uniformly dense film on the top, but a porous inhomogeneous layer at the bottom. This was attributed to fast deposition of coarse particles and/or agglomerates at large electric fields. After drying, micro-sized particles led to a uniform crack-free interface while nano-particles resulted in fragmented non-cohesive layers. Weight loss...
A case study in vapor phase synthesis of Mg-Al alloy nanoparticles by plasma arc evaporation technique
, Article Chemical Engineering Journal ; Volume 259 , 2015 , Pages 918-926 ; 13858947 (ISSN) ; Derakhshan, R ; Mirzaee, O ; Sharif University of Technology
Elsevier
2015
Abstract
Alloy nanoparticles in the Mg-Al system were prepared by plasma arc discharge method from the Mgx to Al (45%
Dynamic modeling and optimization of asphaltene deposition in reservoir rocks using genetic algorithm
, Article 72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 ; Volume 6 , 2010 , Pages 4291-4295 ; 9781617386671 (ISBN) ; Kharrat, R ; Hemmatfar, V ; Ghotbi, C ; Sharif University of Technology
Society of Petroleum Engineers
2010
Abstract
Asphaltene deposition is a problematic challenge for oil production. Changes in key parameters like pressure and fluid composition during natural depletion and different gas injection scenarios may result in asphaltene precipitation and deposition. In this work, a model is developed by application of mass balance equations, momentum equation, asphaltene deposition and permeability reduction models. An algorithm is developed to perform iterative procedure to solve the numerical equations that contains highly coupled variables. Indeed, an equation is introduced to calculate the saturation of the precipitated asphaltene phase. Model parameters were determined by genetic algorithm which is a...
Inhibitory effects of functionalized indium doped ZnO nanoparticles on algal growth for preservation of adobe mud and earthen-made artworks under humid conditions
, Article International Biodeterioration and Biodegradation ; Volume 127 , Febraury , 2018 , Pages 209-216 ; 09648305 (ISSN) ; Mallakin, A ; Malekmohammady, F ; Khosravi Nejad, F ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this article, indium doped ZnO nanoparticles (alloy nanoparticles) were investigated as inhibitors against algae growth on adobe mud and earthen artworks for surface preservation from destruction caused by micro-organisms under humid conditions, through surface modification and activation run off. Nanoparticles (NPs) were fabricated by physical vapor deposition (PVD) growth mechanism. The fabricated NPs were approximately 20 nm in size. The Chlorella vulgaris and Scenedesmus quadricauda were tested by application of indium doped ZnO nanoparticles (In/ZnO NPs) as inhibitors. As concentrations of NPs increased, the negative impacts of NPs on the algal growth were enhanced and physical...
The role of reactants and droplet interfaces on nucleation and growth of ZnO nanorods synthesized by vapor-liquid-solid (VLS) mechanism
, Article Journal of Alloys and Compounds ; Volume 455, Issue 1-2 , 2008 , Pages 353-357 ; 09258388 (ISSN) ; Madaah Hossein, H. R ; Ghamsari, M. S ; Sharif University of Technology
2008
Abstract
Short ZnO nanorods and long ZnO nanowires have been produced on SiO2 and Si substrates by VLS and VS mechanisms via a double tube chemical vapor transport and condensation (CVTC) process. The role of reactants and droplet interfaces on the nucleation and growth of ZnO nanorods have been investigated. A conceptual model for nucleation of ZnO nanorods has been proposed by describing the half-oxidation and reduction reactions at the growth front. The importance of Zn vapor in the nucleation phenomena has been studied by changing starting materials. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and EDX analysis have been used to characterize ZnO nanorods and investigate the...
Aluminum coatings on cotton fabrics with low temperature plasma of argon and oxygen
, Article Surface and Coatings Technology ; Volume 201, Issue 9-11 SPEC. ISS , 2007 , Pages 5646-5650 ; 02578972 (ISSN) ; Ghoranneviss, M ; Moazzenchi, B ; Anvari, A ; Rashidi, A ; Sharif University of Technology
2007
Abstract
In this article, we have studied the properties (especially water repellency) of cotton coated by a thin layer of aluminum. The process has been performed in a low temperature plasma medium, using a magnetron sputtering device. We have also investigated the effect of different gases such as argon and oxygen as the discharge medium on the properties of the obtained samples. The results which are exposure time dependent show a good repellent property for 30 min of treating in argon medium under the condition of our experiment. However, when O2 is used in the system, the cotton property changes to become hydrophilic of which the factor decreases as we increase the time of treating. © 2006...
Three-dimensional modeling of density current in confined and unconfined channels
, Article 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006, Chicago, IL, 5 November 2006 through 10 November 2006 ; 2006 ; 08888116 (ISSN); 0791837904 (ISBN); 9780791837900 (ISBN) ; Firoozabadi, B ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2006
Abstract
Dense underflows are continuous currents which move down-slope due to the fact that their density is heavier than that ambient water. In this work, 2-D and 3-D density current in a channel were investigated by a set of experimental studies and the data were used to simulate the density current. The velocity components were measured using Acoustic Doppler Velocimetry (ADV). The height of density current (current's depth) was also measured. In this study, the density current with a uniform velocity and concentration enters the channel via a sluice gate into a lighter ambient fluid and moves forward down-slope. A low-Reynolds number turbulent model (Launder and Sharma, 1974) has been applied to...
Molecular dynamics of single wall carbon nanotube growth on nickel surface
, Article Computational Materials Science ; Volume 36, Issue 1-2 , 2006 , Pages 117-120 ; 09270256 (ISSN) ; Gorjizadeh, N ; Nasrollahi, Z ; Sharif University of Technology
2006
Abstract
Growth mechanism of a single wall carbon nanotube on the surface of a nickel nanoparticle in the CVD method has been investigated by classical molecular dynamics method. Using first principles methods, we have first constructed a classical potential to describe the interaction between a carbon atom and the nickel surface. The important ingredient in this potential is its coordination number dependence, which also provides the key to the growth mechanism of the nanotube. From the simulations, it is proposed that the growth of an armchair nanotube takes place via attachment of dimers to its end which is in contact with the nickel surface. The effect of nickel nanoparticle's radius on the...
Pre-deposited alkali (Li, Na, K) chlorides layer for effective doping of CuInSSe thin films as absorber layer in solar cells
, Article Solar Energy ; Volume 231 , 2022 , Pages 694-704 ; 0038092X (ISSN) ; Bagher Ghorashi, S. M ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
We introduce an effective method for copper indium sulfide selenide (CISSe) doping with different alkali metals (Li, Na and K) based on a pre-deposited alkali chloride layer. A simple and fast spray method is used for pre-deposition of alkali chloride layer (LiCl, NaCl, KCl) on substrate surface before spray pyrolysis deposition of copper indium disulfide CuInS2 (CIS) films followed by selenization. The different properties of alkali-doped CISSe films by the alkali chloride pre-deposition (ACPD) method were compared to the post-deposition treatment (PDT) method. Based on FESEM images, a highly compact film with large grains can be obtained for CISSe films doped with K(∼0.72 μm) and Na (∼0.56...
Applying a realistic novel ventilation model based on spatial expansion of acini in a stochastic lung
, Article Scientia Iranica ; Vol. 21, issue. 2 , 2014 , pp. 358-369 ; ISSN :10263098 ; Monjezi, M ; Saidi, M. S ; Pishevar, A ; Sharif University of Technology
Abstract
In this paper, particle deposition in the upper airways and five lobes of a human lung is simulated. The simulation is based on a stochastic lung model, derived from detailed morphometric measurements. Pathways are simulated using Monte Carlo methods consequently the whole structure changes both stochastically and statistically in each simulation. In this investigation the termination phenomena is a function of each daughter's diameter which best satisfies the lung's morphometry. Complementary to the previous available assumptions, i.e. flow divisions according to the ratio of daughter's cross sections or distal volumes, in this investigation flow rates are computed in an upward manner...
A comparative study of sequentially layer-deposited and co-deposited Co-Mn oxides as potential redox capacitors
, Article Journal of Solid State Electrochemistry ; Volume 16, Issue 4 , April , 2012 , Pages 1561-1569 ; 14328488 (ISSN) ; Jafarzadeh, S ; Sharif University of Technology
2012
Abstract
Layers of cobalt and manganese oxides were co-deposited or deposited on top of each other or next to each other by potentiostatic method onto stainless steel substrate. Deposition potentials of 1 and -1 V for the anodic and cathodic depositions were employed. Specific capacitance values in the range of 38.5-78 F g -1 were found with cobalt oxide on top of manganese oxide having the lowest and manganese oxide on top of cobalt oxide having the highest capacitances. The usefulness of the electrodes was characterized by cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy in 2 M NaOH electrolyte for redox supercapacitor applications. The latter presented the...
A study of the electrophoretic deposition of bioactive glass-chitosan composite coating
, Article Ceramics International ; Volume 38, Issue 1 , January , 2012 , Pages 471-476 ; 02728842 (ISSN) ; Afshar, A ; Sharif University of Technology
2012
Abstract
Bioactive glass is coated on implant's surface to improve corrosion resistance and osseointegration, when placed in the body. Bioactive glass particles were synthesized through a sol-gel process and deposited along with chitosan to form a composite coating on a stainless steel substrate using electrophoretic deposition technique. Stable suspensions of chitosan-bioactive glass were prepared using bioactive glass particles (<1 μm) and 0.5 g/l chitosan solution. The influence of ethanol-water ratio on deposition yield was investigated. For all process conditions, best results were achieved with suspension of 30 vol% water in ethanol-water containing 2 g/l bioactive glass. FTIR studies showed...
Investigation of asphaltene deposition mechanisms during primary depletion and CO2 injection
, Article Society of Petroleum Engineers - 9th European Formation Damage Conference 2011, 7 June 2011 through 10 June 2011 ; Volume 1 , June , 2011 , Pages 223-231 ; 9781617829673 (ISBN) ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
2011
Abstract
Asphaltene deposition causes serious problems in the oil industry. Variation of oil composition and reservoir pressure is reported to be the most important factors that influence asphaltene deposition from reservoir oil. In this study, a mathematical model was developed to simulate asphaltene deposition during primary depletion and CO2 injection. The main purpose of this study is to investigate and to compare asphaltene deposition mechanisms due to primary depletion and CO2 injection. The solid model as thermodynamic model was applied to investigate asphaltene precipitation. A numerical model was established to the governing equations both in space and time and model parameters were...
Experimental study and mathematical modeling of asphaltene deposition mechanism in core samples
, Article Oil and Gas Science and Technology ; Volume 70, Issue 6 , Nov , 2015 , Pages 1051-1074 ; 12944475 (ISSN) ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
Editions Technip
2015
Abstract
In this work, experimental studies were conducted to determine the effect of asphaltene deposition on the permeability reduction and porosity reduction of carbonate, sandstone and dolomite rock samples using an Iranian bottom hole live oil sample which is close to reservoir conditions, whereas in the majority of previous work, a mixture of recombined oil (a mixture of dead oil and associated gas) was injected into a core sample which is far from reservoir conditions. The effect of the oil injection rate on asphaltene deposition and permeability reduction was studied. The experimental results showed that an increase in the oil injection flow rate can result in an increase in asphaltene...
Tribological properties of Ni–P–SiO2 nanocomposite coating on aluminum
,
Article
Colloid Journal
;
Volume 77, Issue 5
,
September
,
2015
,
Pages 628-634
;
1061933X (ISSN)
; Afshar, A
; Jazani, M. A
;
Sharif University of Technology
Maik Nauka Publishing / Springer SBM
2015
Abstract
In this study, the effects of different concentrations of SiO2 nanosized particles in the bath on deposition rate, surface morphology and wear behavior of Ni–P–SiO2 composite coatings were investigated. The rate of coating deposition was influenced by the incorporation of SiO2 particles. The observations of microstructural morphology were performed with field emission scanning electron microscopy. The amount of deposited SiO2 was examined by X-ray energy dispersive analysis. The results showed that for the coating produced at 12.5 g/L of nanoparticles, the amount of co-deposited SiO2 nanoparticles and microhardness reached their maximal...
CVD fabrication of carbon nanotubes on electrodeposited flower-like Fe nanostructures
, Article Journal of Alloys and Compounds ; Volume 507, Issue 2 , 2010 , Pages 494-497 ; 09258388 (ISSN) ; Torabi, M ; Kajbafvala, A ; Zanganeh, N ; Bayati, M. R ; Molaei, R ; Zargar, H.R ; Sadrnezhaad, S. K ; Sharif University of Technology
Abstract
Galvanostatic method was used to electrodeposit Fe nanostructures on platinum electrodes as catalysts. Scanning electron microscopy (SEM) revealed flower-like Fe deposits with high surface area. Carbon nanotubes were grown on flower-like Fe nanostructures by chemical vapor deposition. The structure of the synthesized carbon nanotubes was investigated by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction. According to X-ray diffraction patterns, Fe was the only detected constituent of the deposited coating. The carbon nanotubes had small wall-thickness and wide hollow core
An Investigation on the electrochemical behavior of the co/cu multilayer system
, Article Journal of Nanoscience and Nanotechnology ; Volume 10, Issue 9 , September , 2010 , Pages 5964-5970 ; 15334880 (ISSN) ; Dolati, A ; Sharif University of Technology
2010
Abstract
Co/Cu multilayers were deposited in a sulfate solution by controlling the current and potential for the deposition of cobalt and copper layer respectively. The electrochemical behavior of these multilayers was studied by cyclic voltammetry and current transients. In addition, a mathematical analysis was used to characterize the electrodeposition system. Simultaneously, the nucleation and growth mechanisms were monitored by these techniques. In this case, the results clearly showed that electrodeposition of cobalt layers was a kinetically controlled process while the reduction of copper ions was a diffusion-control process. Although nucleation mechanism of the single Co deposit was found as a...